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Feb 4, 2017

Eliminating Virtual Asteroids and Virtual Impactors for 2017 BL30

Astrometrica object verification window-- the NEO 2017 BL30
from Siding Spring Observatory, Coonabarabran, NSW, Australia. (MPC Q62)
a stack of 6 - 60-second luminance BIN2 images taken with iTelescope.net's
(TEL T27 0.70-m f/6.6 reflector + CCD)
(C) Steven M. Tilley
NOTE with only a five days data-arc span there is "little" known about the NEO 2017 BL30, and the information in this post may become outdated. So one should always check the links for updates. Whenever an object is listed on one the risk lists (especially if it has a Torino Scale 1 or greater) and it is observable, observers will take a particular interest in it. In the coming days, it is possible there will be more follow-up observations and a search in archives for precovery observations. It is MOST likely this object will be removed from the risk lists. It could take observations over one or more orbital periods before we can reliably say where it will be from 2029 to 2088

Why observe asteroids? 

One of the purposes of observing an asteroid is to reduce the orbital uncertainty of the asteroid. Each observations records were in the sky the asteroid was seen from the given location at the given time. Given that an asteroid's orbit and position within its orbital path determines where in the sky the asteroid can be seen from a location at a given time, many observations over an extended period of time can significantly reduce the orbital uncertainty. 

Each asteroid will be found somewhere within its uncertainty region. If the asteroid as a well-known orbit the uncertainty region will be tiny however if the asteroid as a poorly known orbit the uncertainty region will be enormous and may wrap around the solar system more than once. The question is will the "uncertainty region" of the asteroid and the Earth collide, and if so what is the percentage of the uncertainty region will be taken up by the Earth. The greater the percentage, the greater the risk of impact. As more observations come in the size of the uncertainty region will get smaller this may increase the proportion of the uncertainty region that will be taken up by the Earth. Therefore the "risk" may increase before dropping to zero.

To this end observers from around the world painstakingly take observations of asteroids on the risk lists. Each set of observations eliminates many possibilities(virtual asteroids) where the asteroid may be in the future. Most likely after more observations come all the virtual impactors will be eliminated and 2017 BL30 will be removed from the risk lists. 


Background
(as of 2017-02-03) 

NOTE 99.93500000% chance 2017 BL30 will miss the Earth(i.e. NOT worry about it)

  • Object: 2017 BL30
  • Approximate Diameter:  56 m - 130 m ( 183.727 feet to feet 426.509)(Absolute Magnitude: H= 23.384)
  • Orbit Type: Apollo [NEO]- Potentially Hazardous Asteroid
  • On the Sentry Risk Table: yes
    •  NOTE this is NOT a prediction of an impact but rather a statement there is insufficient observational data rule out an impact -- for information read  Understanding Risk Pages by Jon Giorgini
  •  Torino Scale(JPL): 1 
    • "A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0."
  • On the NEODyS CLOMON2 risk page: yes
  • Torino Scale(NEODyS CLOMON2): 1
  • Discovery (First) observation was made: 2017 01 28.37792 
  • Discovery (First )observation was made by: Pan-STARRS 1, Haleakala (MPC Code  F51 ) The Discovery M.P.E.C.:  MPEC 2017-B125: 2017 BL30
  • Last Observation(publish) was made: 2017 02 02.61107 (by iTelescope Observatory, Siding Spring   (MPC Code Q62 )
  • Data-Arc Span(publish) :  5 days
  • Number of Optical Observations(published) : 60
  • Observatories Reporting (Published) Observations(MPC Code):
    • (246) Klet Observatory-KLENOT. Czech Republic.
    • (595) Farra d'Isonzo, Italy.
    • (691) Steward Observatory, Kitt Peak - Spacewatch, US/Arizona.
    • (F51) Pan-STARRS 1, Haleakala, US/Hawaii.
    • (H06) RAS Observatory, Mayhill, US/New Mexico.
    • (I52) Steward Observatory, Mt. Lemmon Station, US/Arizona.
    • (K88) GINOP-KHK, Piszkéstető, Hungary.
    • (Q62) iTelescope Observatory, Siding Spring, Australia/NSW.
    • (T12) Mauna Kea-UH/Tholen NEO Follow-Up (2.24-m), US/Hawaii.
    • (U69) iTelescope SRO Observatory, Auberry, US/California.
  • Perihelion Distance: 0.862683125221094 (AU)
  • Aphelion Distance: 1.404699667514954  (AU)
  • Earth MOID:  9.67363E-5 AU ( 0.038 (LD)) or 8,992.201 miles (14,471.544 (KM))-- to put things in perspective "If" the Earth Was the Size of a Basketball this would be 10.65(27.06 CM)
  • Next Close-Approach to Earth:  Will safely pass Earth on 2017-Mar-09  at a Nominal Distance of  0.0629444338149308 (AU) (24.496 (LD)) or 9,416,353.271 5,851,050.658 miles (9,416,353.271 KM)) -- to put things in perspective "If" the Earth Was the Size of a Basketball this would be 577.63 feet(176.06)




Jan 30, 2017

The Near-Earth Object 2016 WF9 , the Flyby, the Hullabaloo, and the Facts

The Discovery

An artist’s rendition of 2016 WF9 as it passes Jupiter’s orbit inbound
toward the Sun. Image: Courtesy NASA/JPL-Caltech
On 2016 November 27 at 6:27:07.77(UTC) the NEOWISE project took the first of a series of images of a "new object." A report for this new object was submitted to the Minor Planet Center(MPC) The "object"(with its observations) was posted to the NEO Confirmation Page. Observers from four other observatories submitted follow-up observations, and on 2016 November 30, 04:19 (UTC) the MPC issued a Minor Planet Electronic Circular (MPEC 2016-W125: 2016 WF9) announcing the discovery. This object was given the provisional designation 2016 WF9. This designation tells the world that this asteroid was discovered in the year 2016 during the half-month of November 16-30(W) and it was the 231st(F9) discovery of that half-month.

Follow-up After Discovery 

After the MPC had issued The Minor Planet Electronic Circular announcing the discovery, follow-up observations were made, and prediscovery observations were found adding up to a total of 61 observations spanning 111 days. Each observations records were in the sky 2016 WF9 was seen from the given location at the given time. Given that asteroid and comets follow the laws of planetary motion and move through the solar system in elliptical orbits each observation eliminates many  possibilities of where in the solar system the asteroid can be in the future. Near-Earth Object observational data is generally made available within 24 hours after it is submitted to the MPC.  Anyone who has the knowledge and the software can do their own orbit determination. The available observational data for 2016 WF9 rules out any impact for the foreseeable future.  It should also be noted that observations from other observatories serve as a cross check.

What set 2016 WF9 apart from other Near-Earth Objects is first it has a Tisserand Parameter of 2.893. Most asteroids have a Tisserand Parameter greater than 3, and most Jupiter Family Comets have a Tisserand Parameter between 2 and 3. In other words, it has a "comet-like" orbit.  The second thing about 2016 WF9 is it is rather dark. Given that  2016 WF9 has a "comet-like" orbit and is rather dark lends astronomers to believe it may have cometary origins; however, no cometary activity has been observed yet. 

2016 WF9 Comes to the  Attention of the General Public

On December 29, 2016, NASA call 2016 WF9 to the attention of the public at large by issuing the press release titled "NASA's NEOWISE Mission Spies One Comet, Maybe Two." The press release reported information about the comet C/2016 U1 NEOWISE and 2016 WF9 including information on an unremarkable close-approach and stated: "The trajectory of 2016 WF9 is well understood, and the object is not a threat to Earth for the foreseeable future." In the days that follow this story was picked up by other news outlets, some which blurred the line between journalism and creative writing.

Keep in mind as a story moves through the blogosphere it changes like the "telephone game." The original story is misread, poorly translated, misunderstood, etc. then rewritten by other writers with the wrong information. Then other writers then use the revised story as a source for new stories adding to the madness. One should seek out the original story(and see if it is reliable).
Background
(as of 2017-01-29 ) 
  • Object: 2016 WF9
  • Orbit Type:  Apollo [NEO] Potentially Hazardous Asteroid (NOTE: this is over hundreds if not  thousands of years
  • Approximate Diameter:   270 m - 590 m( 885.827 feet to  1935.696 feet)(Absolute Magnitude: H= 20.2)
  • On the Sentry Risk Table: No (Removed ) 2016-12-20 16:00
  • On the NEODyS CLOMON2 risk page: No (Removed )
  • First(Precovery) Observation was made: 2016 10 10.42213
  • First(Precovery) Observed by: Pan-STARRS 1, Haleakala (MPC Code F51) The Precovery  M.P.E.C.: MPEC 2017-A66 : DAILY ORBIT UPDATE (2017 JAN. 9 UT)
  • Discovery (First) observation was made: 2016 11 27.26884
  • Discovery (First )observation by: NEOWISE (MPC Code C51)The Discovery M.P.E.C.: MPEC 2016-W125: 2016 WF9
  • Last Observation (publish): 2017 01 29.18221  (by  LPL/Spacewatch II (MPC Code 291 )  )
  • Data-Arc Span (publish): 111 days
  • Number of Optical Observations(published): 61
  • Observatories Reporting (Published) Observations(MPC Code):
    • (291) LPL/Spacewatch II, US/Arizona. 
    • (474) Mount John Observatory, Lake Tekapo, New Zealand.
    • (807) Cerro Tololo Observatory, La Serena, Chile. 
    • (C51) NEOWISE
    • (F51) Pan-STARRS 1, Haleakala, US/Hawaii.
    • (Q64) Siding Spring-LCOGT B, Australia/NSW.
    • (T12) Mauna Kea-UH/Tholen NEO Follow-Up (2.24-m), US/Hawaii.
  • Perihelion Distance: 0.9817420310009939(AU)
  • Aphelion Distance:  4.759885397693941
  • Earth MOID: 0.0145594 AU ( 5.666 (LD)) or 1,353,380.78  miles (2,178,055.239 (KM))
  • Next Close-Approach to Earth:  Will safely pass Earth on 2017-Feb-25 at a Nominal Distance of  0.340740651006311 (AU) (132.607 (LD)) or  31,673,822.283 miles (50,974,075.848 (KM)) to put things in perspective "If" the Earth Was the Size of a Basketball this would be  ~ 3,126.54 feet (952.97meters) away) 
Correction


This past has been corrected to show that 2016 WF9 was at one listed on the JPL Sentry and NEODyS risk list. see The Tracking News 30 November 2016 #2016 WF9 The author thanks the reader for the correction,




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Jan 28, 2017

The Comet C/2015 V2 (JOHNSON) Then and Now

Images from 2017-01-26

An image of the Comet C/2015 V2 (JOHNSON) on 2017-01-26
from Mayhill, New Mexico (New Mexico Skies) (MPC Code H06),
a stack of 50-60 Second Luminance BIN1 Images taken with itelescope.net's
(TEL T11 0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer)
(c) Steven M. Tilley
An image of the Comet C/2015 V2 (JOHNSON) on 2017-01-26 
from Mayhill, New Mexico (New Mexico Skies) (MPC Code H06),
a stack of 4-60 Second Luminance BIN1 Images taken with itelescope.net's 
(TEL T11 0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer) 
(c) Steven M. Tilley
An image of the Comet C/2015 V2 (JOHNSON) on 2017-01-26 
from Mayhill, New Mexico (New Mexico Skies) (MPC Code H06),
a stack of 4-60 Second Luminance BIN1 Images taken with itelescope.net's 
(TEL T11 0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer) 
(c) Steven M. Tilley

An image of the Comet C/2015 V2 (JOHNSON) on 2017-01-26 
from Mayhill, New Mexico (New Mexico Skies) (MPC Code H06),
a stack of 4-60 Second Luminance BIN1 Images taken with itelescope.net's 
(TEL T11 0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer) 
(c) Steven M. Tilley
An image of the Comet C/2015 V2 (JOHNSON) on 2017-01-26 
from Mayhill, New Mexico (New Mexico Skies) (MPC Code H06),
a stack of 4-60 Second Luminance BIN1 Images taken with itelescope.net's 
(TEL T11 0.50-m f/6.8 reflector + CCD + f/4.5 focal reducer) 
(c) Steven M. Tilley201

Images from 2015-11-04


Confirmation image of Comet C/2015 V2 (JOHNSON) on 2015-11-04 05:18:08 (UTC)
4 x 60 Sec Stacked @ 0.292 "/min P.A. 13.7 MPC Code H06 using itelescope.net's
(TEL T11 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer) (c) Steven M. Tilley
Confirmation image of Comet C/2015 V2 (JOHNSON) on 2015-11-04 05:23:13 (UTC)
4 x 60 Sec Stacked @ 0.292 "/min P.A. 13.7 MPC Code H06 using itelescope.net's
(TEL T11 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer)(c) Steven M. Tilley
Confirmation image of Comet C/2015 V2 (JOHNSON) on 2015-11-04 07:00:27 (UTC)
4 x 60 Sec Stacked @ 0.292 "/min P.A. 13.1 MPC Code H06 using itelescope.net's
(TEL T11 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer)(c) Steven M. Tilley
Confirmation image of Comet C/2015 V2 (JOHNSON) on 2015-11-04 07:08:00 (UTC)
4 x 60 Sec Stacked @ 0.292"/min P.A. 13.1 MPC Code H06 using itelescope.net's
(TEL T11 0.50-m f/6.8 astrograph + CCD + f/4.5 focal reducer)(c) Steven M. Tilley


Other links:

Jan 22, 2017

Virtual Asteroids, The Observatory's Cat, a Lost Car Key, and 2012 TC4 Beyond the 2017-Oct-12 Close-Approach

The Second Part in a Series

An artist’s rendition of 2016 WF9 as it passes Jupiter’s orbit inbound toward
the Sun. Image: Courtesy NASA/JPL-Caltech
Now I plan to give some background on the subject of virtual asteroids and virtual impactors. While asteroid researchers know this topic well this is for the non-researchers, I am going to explain the subject by way of a silly story,

The Observatory's cat and the Lost Car Key

There was an observatory that hosted a monthly Astronomy and Ice Cream Night. This event would consist a free talk on Astronomy and ice cream(at a nominal cost). At the end of one of the events the professor who gave that night's talk discovers he had lost his car key. Everyone knew that the key had to be at the observatory. First, they sent security out to keep an eye on the parking lot, then they started checking under the tables, by the display cases, the podium, and the trash cans. Many other keys were found when asked "is this your key?" the professor said "no." One thing that set this observatory apart was it was adopted by a cat named OC(A.K.A Observatory Cat). OC loved ice cream, and OC was found with the key licking ice cream off it when asked "is this your key?" the professor said "yes" and drove home.

If we think of the story this way, there is a large number of "virtual" keys. One for each "possibility" where the "real" key "may be," as places were searched the "virtual" keys were eliminated. They could not rule out that someone had the key and would steal the car this risk would be a great risk if the vehicle is easy to find in a small lot. On the other hand, if the lot were enormous the and the car was hard to locate the risk would be lower. There may be many keys so one can not assume that they found the key because only one key will start the car. The cat would be the Yarkovsky Effect and gravitational perturbations, the cat moved the key but kept it at the observatory, 

 Now Back to Asteroids

One thing to remember is unlike, car thieves, cats, and lost car keys asteroids follow the laws of planetary motion. Asteroids move through an extensive solar system in elliptical orbits. An asteroid's orbit and position within its orbital path determines where in the sky the asteroid can be seen from a location at a given time. When astronomers(professional and amateur) observe an asteroid, they record its coordinates(sky position) along with the day and time, apparent magnitude, and a code for their location. An asteroid's orbit is determined by finding an orbit that best places it in the sky as it was observed from the given location at the given time.

When it comes to orbit determination there is no such thing as "the" orbit for any asteroid, tiny observational errors come into play. The solution is to generate an enormous number of slightly different orbits that fit the observations acceptably well. Each orbit has it own virtual asteroid.  There is an uncertainty region containing the virtual asteroids.  The "real" asteroid is somewhere within the uncertainty region. After each set of new observations, the orbits are re-generated, and like reality game shows contestants, many virtual asteroids are eliminated.  As time moves forward, the virtual asteroids will move apart from each other. If the asteroid goes unobserved for an extended time, the uncertainty region can become enormous and sometimes can wrap around the solar system more than once.  

Through the use of computers, the positions of the virtual asteroids can be projected into the future, while accounting for the Yarkovsky Effect; and the gravitational forces of the Sun, The Earth, Our Moon, the other planets, and the large asteroids. If any virtual asteroids impact the Earth, they are known as virtual impactors. The percentage of virtual asteroids that "impact" the Earth is used to estimate the risk the "real" asteroid could "impact" the Earth. If the risk is greater than 1 in 10 billion, the asteroid is placed on the risk lists. Asteroids on the risk lists are rated on the Palermo Technical Impact Scale which compares the risk from the asteroid to the risk from all asteroids and the Torino Scale(for the next 100 years) which is used to communicates the level of risk from the asteroid to the public. Whenever an asteroid is posted to one the risk lists, and it is observable, observers will take a particular interest in it. Follow-up observations may be attempted and there maybe a search in archives images for precovery observations.

When reading the risk lists, one should keep in mind that the risk lists are NOT a prediction of an impact or even a close-approach. The "real" asteroid could be on the other side of the solar system when the virtual asteroid "impacts." Also keep in mind as new observations are reported the asteroid will most likely be removed from the risk lists; however, the risk may increase before it drops off the list if the "real" asteroid is making an exceptionally close approach to Earth on the date in question, this is normal.

2012 TC4  beyond the 2017-Oct-12 Close-Approach

On 2017-Oct-12 the Earth will be outside of the uncertainty region of 2012 TC4 this rules out an impact from this asteroid on this date. However, based on all available observations made to date the Earth will pass through the uncertainty region of 2012 TC4 on 2020-Oct-11.72, and there will be a 1 in 1,613,000 chance of impact. The risk does not stop there from 2020 to 2114 there will be 79  Potential Impacts of 2012 TC4 with a cumulative risk of 1 in 12,000 chance of impact. 2012 TC4 could be observed during this year's apparition. If "new" observations are taken the orbits will be re-generated, and like reality game shows contestants, many virtual asteroids will be eliminated. Most likely any risk for the next 100 year will be ruled out.

[!!!Note you are reading this after Fall of 2017 Check for Updates!!!]




Background and Sources
(as of 2017-01-21) 
  • Object: 2012 TC4
  • Orbit Type: Apollo [NEO]
  • Approximate Diameter: 15 m - 33 m (  49.2126 feet to 108.268  feet)(Absolute Magnitude: H= 26.7)
  • On the Sentry Risk Table:  Yes 
    •  NOTE this is NOT a prediction of an impact but rather a statement there is insufficient observational data rule out an impact -- for information read  Understanding Risk Pages by Jon Giorgini
  • Torino Scale 0
    • "The likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.."
  • On the NEODyS CLOMON2 risk page: Yes
    • NEODyS Recovery Campaign: 2017-08-31 to 2017-10-24
  • Discovery observation was made: 2012 10 04.467661
  • Discovery observation was made by Pan-STARRS 1 (MPC Code F51) The Discovery M.P.E.C.: MPEC 2012-T18 : 2012 TC4
  • Last Observation (publish): 2012 10 11.74842 (by Volkssternwarte Drebach, Schoenbrunn(MPC code 113))
  • Data-Arc Span (publish): 7 days
  • Number of Optical Observations(published):301
  • Observatories Reporting (Published) Observations(MPC Code):
    • (089) Nikolaev,  Ukraine.
    • (104) San Marcello Pistoiese, Italy.
    • (113) Volkssternwarte Drebach, Schoenbrunn, Germany.
    • (204) Schiaparelli Observatory, Italy
    • (291) LPL/Spacewatch II, US/Arizona.
    • (300) Bisei Spaceguard Center-BATTeRS, Japan.
    • (461) University of Szeged, Piszkesteto Stn (Konkoly), Hungary.
    • (470) Ceccano, Italy.
    • (568) Mauna Kea, US/Hawaii.
    • (695) Kitt Peak, US/Arizona.
    • (703) Catalina Sky Survey, US/Arizona.
    • (716) Palmer Divide Observatory, Colorado Springs, US/Colorado.
    • (718) Tooele, US/Utah.  
    • (857) Iowa Robotic Observatory, Sonoita, US/Arizona.
    • (900) Moriyama, Japan.
    • (932) John J. McCarthy Obs., New Milford,  US/Connecticut.
    • (B04) OAVdA, Saint-Barthelemy, Italy. 
    • (B88) Bigmuskie Observatory, Mombercelli, Italy.
    • (C32) Ka-Dar Observatory, TAU Station, Nizhny Arkhyz, Russia.
    • (C77) Bernezzo Observatory, Italy.
    • (E10) Siding Spring-Faulkes Telescope South, Australia/NSW.
    • (F51) Pan-STARRS 1, Haleakala, US/Hawaii
    • (F65) Haleakala-Faulkes Telescope North, US/Hawaii.
    • (G40) Slooh.com Canary Islands Observatory, Canary Islands (Spain).
    • (G48) Doc Greiner Research Obs., Rancho Hildalgo,  US/New Mexico.
    • (H06) iTelescope Observatory, Mayhill, US/New Mexico.  
    • (H17) Angel Peaks Observatory, US/Colorado.
    • (H21) Astronomical Research Observatory, Westfield, US/Illinois.
    • (H36) Sandlot Observatory, Scranton, US/Kansas
    • (J16) An Carraig Observatory, Loughinisland, UK.
    • (J84) South Observatory, Clanfield, UK.
    • (J95) Great Shefford, UK.
  • Perihelion Distance: 0.9337184081730526(AU)
  • Aphelion Distance: 1.877515914032821
  • Goldstone Asteroid Schedule: Yes  2017 Oct ( Needs Astrometry: Yes Physical Ob
  • Near-Earth Object Human Space Flight Accessible Targets Study (NHATS): Yes
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